Universal color base for coating compositions



United States Patent O 3,497,374 UNIVERSAL COLOR BASE FOR COATING COMPOSITIONS Vernon G. Nix, Park Forest, 111., assignor to The Sherwin- Williams Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Filed Jan. 24, 1967, Ser. No. 611,258 Int. Cl. C08h 1/34, 17/32; C08j 1/36 US. Cl. 106-308 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to improved universal color bases particularly adapted for use in conjunction with a wide variety of lacquer and enamel types of coating compositions, and more particularly to improved universal color bases which are characterized by the presence therein of a novel solvent system, a pigment, and a mixed cyclicaliphatic ester of an oxazoline, the precursor of which is a poly(hydroxy alkyl) amino alkane, especially those which are formed by the treatment of such hydroxy amino compounds with both aliphatic mono-carboxylic acid having an iodine value less than 160, and preferably being saturated, and a monocyclic monocarboxylic acid, to produce a normally liquid material which demonstrates essentially Newtonian behavior, which is non-polymeric, and which is non-drying. The alkyl group contains one carbon atom and alkane groups contain 1 or 2 carbon atoms. These esters are characterized by the presence therein of a heterocyclic ring containing 5 members herein identified as an oxazoline ring.

Automotive coating compositions, and particularly automotive refinishing compositions, for example, are generally of the lacquer type wherein the film forming process is largely due to the removal of solvent at normal or elevated temperatures resulting in the desired film. A substantial volume of business is done in the distribution of base coating compositions of a limited number of formulations, together with a palette, or supply, of concentrated color bases which are to be added to the base coating composition in amount determined by formula, or by other matching techniques, in order to produce a coating composition which matches a predetermined vehicle color, for example. The most usual system involves a formulating machine either automatic or semi-automatic whereby predetermined amounts, e.g., 1 to 4 cc., of one or more color bases are deposited in a relatively larger quantity of a standard base lacquer composition, e.g., 1 quart or 1 gallon, which may or may not contain pigmentary material, and thereafter uniformly blending the pigmentary additions into the base material to arrive at a color which is a match for the color on a given vehicle. Normally, the formulas are provided to the refinishing shop by the automobile manufacturer, or by the suppliers of the original coating compositions.

As indicated, automotive coating compositions, and automotive recoating or refinishing compositions (which will be used herein for illustrative purposes) are generally based on a variety of different systems, principally of the air-drying type, and including nitrocellulose base compositions, oil modified alkyl base compositions, acrylic copolymer base compositions, cellulose acetate butyrate base compositions, poly(methyl methacrylate) base compositions, etc. Under present practice, each of the currently commercially available base coating compositions requires its own palette of colors to be dispersed therein to produce matching color compositions for refinishing purposes. Thus, a refinishing shop is obligated to maintain a number of palettes of colors, each of which may include a relatively large number of color bases, in order that the shop may be able to match a large variety of coating compositions.

By the present invention, it is now possible to provide a single palette of colors, the individual color bases of which are compatible with a wide variety of lacquer and enamel base coating compositions, such as, those which are presently in commercial use.

The solution of the problem of variation in the nature of the lacquer and enamel vehicles used for the original coating of, for example, automotive vehicles, railroad cars, aircraft, woodwork, etc., presents a series of problems in itself which appear to be mutually insoluble, but which by the compositions of the present invention are advantageously and most satisfactorily solved. Illustrative of these problems are the following: First, the concentration of pigment per unit of volume (PVC) must be such as will allow the color bases to be mixed accurately for matching original colors. Ordinarily, paint stores or paint shops have a color dispensing machine, the specifications for which require that one shall be able to dispense one cubic centimeter of color base accurately in order to obtain reproducible colors. The dispensed volumes of the color base are then thoroughly blended with a predetermined quantity of a standard vehicle, e.g., an auto refinish vehicle, to obtain a color match of the same general type coating as originally applied to the given surface. Thus, the ability of the liquid system of the color base, or color base vehicle, to maintain in stable dispersion a substantial quantity of pigmentary material is an important consideration to this invention.

Another important consideration is the nature of the color base vehicle as it affects its compatibility not only with the refinishing base vehicle (that vehicle to which the color base is added), but also its compatibility with a large variety of organic solvent materials.

The next property which is desired concerns the rheological properties of the color base so that the resultant color base will be substantially free from settling of the pigment, substantially free from reactivity of the base vehicle with the pigment, and preferably requiring no agitation whatever on storage in order to maintain a proper dispersion of the pigment in the color base.

Another consideration is that the physical properties of the ultimate coating composition must not be adversely affected. For example, the color base may have a plasticizing effect upon the coating vehicle, and thus change the nature of the final film. Thus, there can be a very fine balance between those color bases which are able to contain a given pigment at relatively low pigment-volume concentrations, and the amount of plasticization which the coating composition vehicle can withstand.

Since these compositions also contain solvent, the effect of these solvents on the drying characteristics of the refinishing vehicle composition is also very important, and this must also be considered in conjunction with the amount of the color base which is required in order to develop a certain shade of color within the base coating composition. The balance necessary that too much solvent is not included in the base composition to adversely aifect the drying characteristics of the composition, but sufficient solvent is included in order to improve the compatibility of that quantity of color base which is added to the base composition again poses a rather difiicult problem.

It has been found that the essentially Newtonian vehicles which are mixed esters of cyclic and aliphatic acids which have been reacted with a tris-(hydroxy-alkyl) amino alkane enable the production of color bases including a maximum amount of pigment for the widest practical range of pigmentary materials, and a solvent system which extends the compatibility of the pigmentcolor base vehicle system to the widest variety of currently available lacquer and enamel types of coating composition systems.

Generally speaking, the color bases of the present invention are characterized by a two-component solvent system and a universal color base, also comprising two essential components.

The solvent system is in itself a novel composition and comprises two ingredients. The first of these is a aromatic compound, preferably an aromatic hydrocarbon. Generally, the aromatic compounds useful in accordance herewith include the plentifully commercially available aromatic hydrocarbons, e.g., benzene, toluene, and xylene. It will be understood, of course, that less readily available aromatic compounds may be used alone or in combination with any of the foregoing, such as, ethyl benzene, mesitylene, tertiary butyl benzene, octyl benzene, di-ethyl benzene, monochloro-benzene, methoxy-benzene, and the like. The particular aromatic compound, or mixture of aromatic compounds will depend upon the solvent volatility which is desired taking into consideration the vehicle system of the base coating composition.

The solvent systems of the present color bases include also a second material which is specifically propylene glycol mono-methyl ether. This ether in combination with the aromatic compound or mixture as above identified constitutes the solvent system for the present color bases.

These individual solvents are generally present in a ratio of from 70:30 to 30:70, respectively, and most usually within the range of from 50:50 to 70:30. It has been found that this solvent system possesses the proper solvent power and the proper evaporation rate for particular utility in the wide variety of base vehicles useful in the automotive refinishing field.

The first essential ingredient of the universal color bases useful in accordance with the present invention is a solid particulate pigmentary material. Pigments vary in their ease of dispersion in color bases of the type of the present invention, just as they vary in their ease of dispersion in other vehicles. It has been determined that the most difliculty dispersible materials currently in wide use are readily dispersed in the vehicles of the present invention to form stable color bases at adequate pigment-volume concentrations, and thus it follows that all other pigments which are more readily dispersable exhibit the same readier dispersibility in the coating compositions of the present invention. Thus, the pigments useful in accordance with the present invention include all solid particulate pigmentary materials which are non-reactive with the present systems, and specifically include titanium dioxide in any of its various pigmentary forms, lampblack, carbon black, ferrite yellow, medium chrome yellow, phthalocyanine blue, both red and green shades, Milori blue, iron oxide, cadmium sulfide, ultramarine blue, chromium oxide, hydrated chromium oxide, phosphotungstic acid green, chrome orange, cadmium selenide, cadmium sulfide, benzidine yellows, Hansa yellows, zinc chromate, phthalocyanine blue, etc. The nature of the pigmentary material makes little or no difference in the color bases of the present invention. Any solid particulate pigmentary material of conventional pigment size, e.g., 325 mesh, or sizes, may be used in accordance with this invention. The fact that the first seven pigmentary materials mentioned above can be used to form satisfactory color base compositions pursuant to this invention is indicative that any other pigmentary may be satisfactory and used successfully.

The second essential ingredient of the universal color bases useful in accodance with the present invention is, as indicated above, a mixed oxazoline-containing aliphatic cyclic ester of an oxazoline, the precursor of which is a tris-(hydroxy-alkyl) amino alkane.

Under the conditions of the formation of these esters there is formed a characterizing heterocyclic ring containing 5 members herein identified as an axozoline ring. Thus, this heterocyclic ring is a characterizing feature of the esters which constitute the principal vehicle of the color bases. More specifically, these esters are formed by reacting with a tris-(hydroxy-alkyl) amino alkane, a relatively high molecular weight aliphatic acid in an amount which is less than that which would be required to satisfy all of the hydroxyl content of the hydroxylamine compound, and a monocyclic mono-carboxylic acid to complete the esterification of the available hydroxyl in the hydroxylamine compound, these acids being added either sequentially or simultaneously.

Where one might expect that a material, such as, tris- (hydroxy-methyl) amino methane, would .be tetra-functional, one of the things which occurs when such a material is reacted in part with an aliphatic carboxylic acid is ring formation whereby an oxazoline ring is formed. Accompanying the ring formation operation, one of the functionalities of the compound is removed. Thus, the tris-hydroxyl-amines are tri-functional as distinct from tetra-functional. In a preferred embodiment, esterification of the hydroxyl groups with an aliphatic carboxylic acid of the straight chain or branched chain type is carried out to the extent of not more than two of the available functionalities, i.e., amine and hydroxyl. The balance of the functional content of the hydroxy alcohol is then satisfied with a cyclic acid, preferably a monocarboxylic aromatic acid. The resulting composition, then, is usually a mixture of mixed aliphatic-cyclic acid esters of the trishydroxy amino compound. The amount, therefore, of the aliphatic acid generally ranges from 0.8 mol to 2 mols of such aliphatic carboxylic acid to 1 mol of the trishydroxy amino compound. The amount of the cyclic carboxylic acid usually ranges therefore, from 2.2 to 1 mol of such acid to each mol of the tris-hydroxy compound, the amount of the cyclic acid in combination with the aliphatic acid, being that which is sufficient to balance stoichiometrically the amine and hydroxyl content of the amino alcohol which is used, or just slightly less.

It becomes convenient at this point to identify still further the nature of the tris-hydroxy amino compound which is useful in accordance with this invention, the nature of the aliphatic carboxylic acid which is useful in accordance herewith, and the nature of the cyclic acid.

As indicated above, the principal building block of the present condensation products is a tris-(hydroxy-alkyl) amino alkane. These materials upon reaction readily form a heterocyclic oxazoline ring, or heterocyclic pentoxazoline or dihydro oxazine ring. Thus, particularly suitable materials for use as the amine and hydroxyl providing portion of the oxazoline-containing esters of this invention include tris-(hydroxy-methyl) amino methane; tris- (hydroxy-ethyl) amino methane; tris-(hydroxy-ethyl) amino ethane; di-(hydroxy methyl) mono-(hydroxy-ethyl) amino methane; tris-(hydroxy methyl) amino ethane; 2-amino-2-methyl-1,3 propanediol, and the like. The preferred material is the tris-(hydroxy-methyl) amino methane.

The aliphatic acids useful in accordance with the present invention are preferably saturated straight chain, or

they may be saturated branched chain. Best results are secured in respect of compatibility with coating compositions of the types above-mentioned when the aliphatic acid is a saturated monocarboxylic group, and especially a terminal iso-, or a tertiary group. The aliphatic acids useful in accordance herewith may contain from 5 to 18 carbon atoms, the preferred aliphatic acids containing from 8 to 12 carbon atoms. These acids are not ordinarily obtainable as pure materials, and consequently, commercial aliphatic acids are used in accordance herewith which commercial acids constitute or comprise mixtures of aliphatic acids containing, for example, from 8 to carbon atoms. As indicated with the commercial mixtures, compounded mixtures of the foregoing aliphatic acids may be employed.

The cyclic acids useful in accordance herewith are monocyclic and .monocarboxylic, preferably aromatic monocarboxylic. Thus, benzoic acid and substituted benzoic acids, e.g., toluic acids, i.e., Z-methyl benzoic acid, 3-methyl benzoic acid, 4-methyl benzoic acid, xylic acids, i.e., hemellitic acid 2,5-dimethyl benzoic acid, 2,6-dimethyl benzoic acid, o-methoxy benzoic acid, m-methoxy benzoic acid, 2-ethyl benzoic acid, p-tert-butyl benzoic acid, p-chlorobenzoic acid; trimethyl benzoic acids, and other alkyl substituted benzoic acids, or alkoxy benzoic acid, or halogen substituted benzoic acids, per se, or natural or synthetic mixtures of such acids, e.g., rosin acids.

The following description, utilizing Tris Amino [tris-(hydroxy-methyl) amino methane] as an example of a preferred starting material, will illustrate theoretical and practical aspects of this invention, it being understood that other amino compounds could be used in a corresponding manner to produce corresponding base vehicle materials.

In the preparation of these Tris Amino condensates for the universal color base vehicle, a mixture of aliphatic and cyclic monocarboxylic acids has been used. The al iphatic acids have included straight and branched chain acids. The cyclic acids have been limited to benzoic, substituted benzoic and rosin acids. All of these acids are listed below with descriptive data.

TABLE I Acid Components-Tris Amino Condensates Acid M. Wt. Description Stht chain- S t earic 284. 47 C13 stiraight chain saturated aci Pelargonic acid. 158 09 strai ht chain acid (nonanoic) Valerie 102 05 straight chain acid (pentanoic).

Branched chain primary:

Isodecanoic acid 172. 27 Dimethyl octanoic, trimethyl heptanoic. i

Isooctanoic acid. 144 Mixture of isomeric branched chain acids with eight carbon atoms.

Isononanoic acid 158 90% 3,5,5-trimethyl hexanoic acid, 107, mixture of isomeric branched 9 carbon atom acids.

ICI 8-10 acid 156 'Irimetliyl hexarioic.

Decanoic acid. 3,4,5-triinethy1 heptanoic.

Secondary:

2-ethyl hexoic acid 144. 22

Tertiary:

Versatic 9-11 acid 184; 187 Mixture of saturated mainly monocarboxylic acids having a C9, C10, On chain length. One R group= CH R2 C--COOH. All R R3 groups= straight chain 10% secondary acid 90% ary.

Small proportion of tertiary acids are cyclic, princi- 7 pally pentane ring cyclics.

2-ethyl, Z-methyl butanoic. N eodecanoic acid Neotridecanoic acid. Substitution similar to neo-decanoic but based on a On chain.

Neotridecanoic acid Aromatic acids:

Benzoic acid 122. 12 Para tertiary butyl benzoic acid. 178. 23 Rosin acids 350 Acidic resin (A.V.

Typical analysis:

Abietic acid18%. Dehydroabietic acid-22%. Dihydroabietic acid Tetiahydroabietic acid PROCESSING PROCEDURES Actual processing of these condensates has involved several variations which may or may not affect their performance. A limited few have been essentially fusion processed but the greater number have been solvent processed.

Solvents used have been mainly toluene and xylene. Solvent concentration has ranged from 2% to 10%. It has been added in various increments controlled to a large degree by the rate of the water liberated. The reflux can become too vigorous when a large amount of solvent is present at a point when substantial amounts of water are being liberated. As high as 10% has been charged, but this is not always feasible. An initial charge of 3%, with the rest added as reflux permits, works well.

Acids have been added in three different ways including (1) initial charge of both aliphatic and cyclic acid, (2) prereaction of the aliphatic acid component and (3) prereaction of the cyclic acid component. The procedure would affect the acid substituent directly attached to the oxazoline ring.

Reactions were monitored by amount of Water evolved, and acid value to determine extent of reaction. Some difficulties were encountered on occasion in achieving the desired acid value. The acid value difiiculty could result from (1) inconsistency in the acid value of the acid; (2) small weight errors; 3) loss of Tris Amino or Tris Amino carboxyllate; and (4) sluggishness of reaction in later stages possibly due to steric hindrance.

A final acid value of 10 is acceptable for most purposes, but water systems may more desirably use a product with an acid value less than 5. Consequently, some condensates were formulated with a deficiency of acid and an excess of hydroxyl to achieve this lower value. This is exemplified later.

The three procedures for processing are described below. They are applicable for both fusion and solvent processing.

(I) The acids are charged to a reaction vessel with agitation, heating source, inert gas inlet, thermometer, condenser and water trap. After heating to 225 F., the Tris Amino is added. Solvent (3%10%) is charged as water reflux will permit. Usually an increment of 3% can be added initially although all 10% has been added. A nitrogen blanket is used as well as solvent. The batch is heated gradually to 395 to 420 F. and held for an acid value of 10 or less. Solvent is removed by blowing and the batch is removed. (See Example 11 in Table II). Top temperature was 397 F. Final acid value was less than 5 because it is an Example 10 type based on a deficiency of acid and an excess of hydroxyl.

(II) The same equipment as above described, would be used. In this case the aliphatic acid would be charged, heated to 225 F. and the Tris Amino added. A nitrogen blanket is used as well as solvent. Three to 10% toluene or xylene can be used as reflux solvent. There have been indications of faster reaction at the 10% level or xylene. Oxazoline ring formation is faster in the presence of higher boiling solvents such as xylene because the tem- (See Examples 9 and 10.)

The specific compositions and procedures delineating these condensates are given below. These examples also show the use of excess hydroxyl with an acid deficiency to achieve the lower acid value condensate. The example numbers refer to an accompanying table where properties are given for a varied group of condensates. These are preferred examples:

Tris Amino isodecanoate benzoate (no excess hydroxyl) Tris Amino-363 g. (3 moles) Isodecanoic acid1038 g. (6 moles) Benzoic acid-366 g. (3 moles) Charge isodecanoic acid into a flask equipped with agitator, condenser, water trap and inert gas. Maintain an inert gas blanket through0ut."Heat to 225 F. Add Tris Amino. Add 5% toluene for reflux. Heat to 350 F. and hold for an acid value of 0-2. Cut heat. Add benzoic acid. Heat to 350 F., then raise temperature to 390-395 F. Hold to an acid value less than 10. (See Example 9 in Table II.)

Tris Amino isodecanoate benzoate (excess hydroxyl) Tris Amino-665 g. (5.5 moles) Isodecanoic acid1903 g. (11 moles) Benzoic acid611 g. (5.01 moles) Charge isodecanoic acid into a flask equipped with agitator, condenser, water trap and inert gas. Maintain inert gas blanket. Heat to 225 F. Add Tris Amino and 5% toluene for reflux. Heat to 350 F. and hold for an acid value of 0-5. Cut heat. Add benzoic acid. Heat to 350 F. initially, then raise temperature to 390-395 F. In the later stages, use a nitrogen blow to implement removal of water. Hold for an acid value of less than 5. (See Example 10 in Table II) Both condensates could also be made by charging all ingredients initially and heating gradually to 350 F. and then to 390-395 F. and holding for final acid value.

(III) The procedure would be the same as (II) except the cyclic acid would be charged first and the reaction continued as above. (See Examples 16 and 17).

As previously explained, Tris Amino will react with three moles of acid. The acid ratios thus have ranged from 3 moles of aliphatic acid to 3 moles of aromatic acid. 'The latter (tribenzoate) was not practical since it was a solid. The most interesting properties seem to result between the 1.5/1.5 and the 2/1 aliphatic to aromatic acid ratio. In the accompanying tables the various molar compositions and acid variations have been delineated. The end product is probably not a single composition, but a family of products. In a mixture of isodecanoic and benzoic acid the product could contain the triisodecanoate, the diisodecanoate-monobenzoate and the monoisodecanoate-dibenzoate providing transfer reactions are limited. This would apply under process II. If process I or III were used the tribenzoate might also be present.

Of the aliphatic acids the branched chain type have been the most successful. It is difficult to state that the position of the branch is critical when considering the differences between versatic acid and isodecanoic or isononanoic acid, since all three have been successful. Perhaps it is primarily the branched character per so which is most important.

TABLE 11 Process Aliphatic Aromatic Reflux Acid Acid Acid Ratio OH/COOH Modified Stage 1 Stage 2 Cook Time n-Nonanoie Benzoic 1. 8/1 1.073 5% toluene gradually 24:40 Iso-deeanoio- Rosin acids-.- 2/1 1. 000 4.2% toluene 20:05 versatic do 1/2 1. 000 28:20 2. 5/0. 5 1. 000 42: 2/1 1. 000 1.4% toluene 19:00 1. 5/1. 5 6.9% toluene gradually 38:00 1/2 5.0% toluene gradually 19:25 2/1 5.0% toluene gradually 28:20 2/1 1.4% toluene 19:00 /0. 91 5% toluene gradually 24:20 2/0. 91 5% toluene gradually 21:05 2/0. 7 5% toluene gradually 30:15 1 83/0. 92 5% toluene gradually 30:45 2/0. 91 1. 031 5% toluene gradually 24:20 2/0. 91 1. 031 One stage- 5% toluene gradually 21:05 2/0. 91 1.031 Benz. tlrst... 5% toluene gradually 29:40 2/0. 91 1.031 -..do 5% toluene gradually 27 :45 1. 5/1. 5 1. 000 3% xy1ene.... 3% xylene--. 11:35 1. 5/ 1. 5 l. 000 10% xylene initially 22:05 1. 5/1. 5 1. 000 Benz. first"... 3% xylene 14:30 2/ 1. 000 3% xy1ene..... 3% xylene..- 10:00 1 /1. 25 1. 000 ..do -do. 12:33 1. 75/1. 0 1.093 do do. 11:50 1. 5/1. 5 1. 000 do .do. 11:35 2/1 1. 000 do -do- 13:05 1 75/1. 25 1. 000 do .do. 11:35 1.75/1 1. 086 do .do. 8:00 1. 5/1. 5 1. 000 .do. do... 27:40 1.5/1.5 1.000 do do 20:20 2/1 1. 000 10% xylene gradually 17:00 1. 5/1. 5 1. 000 10% xylene initially 24:00 1. 497/1. 497 1. 002 10% xylene gradually 25:00 1. 455/1. 455 1. 028 10% xylene gradually 17:45 1. 456/1. 411 1.046 10% xylene gradually 23:50 1. 94/0. 97 1. 031 10% xylene gradually 34:00 1. 94 1. 031 10% xylene gradually 30:00 2/0. 91 1. 031 6% xylene 32:50, 1/1 1. 000 AMPD Z Toluene 1 :00

G-H Viscosity Color G- Percent Solids Acid Value TABLE 1T.Continued Percent Percent Theo. Oxazoline H2O Ring F. Cook Temp.

Stage 1 Stage 2 Gr. No.

Ex. N0.

omi awcmuemnmno nmqmomlemomomnmdnowufiflkamqwfimiomiamd vhlnmomomLomL 99999999999999989899998889899989988984 1.2568595008947890 56721424751640920506 L9 0 RmAmOWQRWZomLQZQWG fiw 0 6 0 &flw7 omfimomqm 4 1 wn 98 8777 7 47 1 alateaaLaeztaezo t taLmanwaaaaaaasa first stage. Reflux cook time.Represents approximate time withthe range of cook temperatures used; heatup times excluded.

, and the which is preferably monocyclic and monocarboxylic, is added and Modifications.i.e., process or composition. Ex.: One Stage.Reactants all charged initially; benzoic firstindicates prereaction of benzoic acid in the first stage rather Process.Fusion or solvent or combination. Solvent addition noted for stage where possible. In some cases addition may be gradual throughout. Arrows indicate continuous presence of solvent charged in Percent theoretical H O.--Represents the percent of water removed versus that theoretically possible. This may vary slightly due to calculation basis, namely (1) total theoretical water or that at this (2) particular acid value. Except where the acid value is high, the difference is not significant.

Percent oxazoline ring.Calculated on final acid value, water removed, and yield solids or approximate yield (charge water removed).

In summary, then, the vehicles of the present invention are preferably produced by first interacting a C -C aliphatic monocarboxylic acid, which is preferably saturated and branched, with the amino alcohol acid value carried to about 5. From 1 to 2.5 moles of aliphatic acid per mole of amino alcohol (Tris Amino compound) are used. Thereafter, the cyclic acid the cooking continued until the acid value is reached. This is usually in the range of from 1 to 10. From 0.5 to 2 moles of cyclic acid per mole of amino alcohol are used, the total of aliphatic and cyclic acid being equal to or slightly less than stoichiometric. When the carboxylic acids are blended prior to reaction with the amino alcohol, the resultingstructure is somewhat uncertain.

The amount of combined aliphatic acid and cyclic acid, whether sequentially or simultaneously reacted with the amino alcohol, is desirably either a stoichiometric ratio or slightly less.

In conducting the esterification reaction, from 0.01% to 1.0% of a catalyst may be employed, although preferalbly not until after ring formation has occurred. Suitable catalysts include triphenyl phosphite and lithium carbonate. With some catalysts, color formation tends to be a 1 PTBBA=Para-tert.-butyl benzoic acid. 9 AMPD=2-amiuo-2-methyl-1,3-propane diol.

TABLE II.-NOTES Group I.Presents the straight chain fatty acid-aromatic acid condensates prepared. Cooking times include h th aliphatic a id (P o 111), both reactions. Characteristics are for the final products.

Group II.Gives the isodecanoic and versatic-rosin acid condensates.

Group III.Presents the various molar ratios of isodecanoic to benzoic acid between (3/0 to 0/ 3) and an isodecanoic para-tert. butyl benzoic acid (PTBBA) condensate. The one stage indicates that all reactants were charged initially.

Group IV.-Presents the various OH/COOH ratios studied in the isodecanoic-benzoic condensate.

Group V.Presents the process variations tried with the excess OH type. These include initial charge of all dients (Example 15) and prereaction of the aromatic acid (Examples 16 and 17). The latter indicates less satisfactory oxazoline ring formation.

Group VI.-Delineates the prereaction of isononanoic acid versus prereaction of benzoic acid. Again oxazoline ring appears lower. (Example 19) was a repeat of Example 18 in which the AV did not drop as desired. The

Groups VII and VlII.-Present the respective isononanoic and isooctanoic-benzoic condensates. Example 29 is a repeat of Example 28 whose temperature hit 480 F.

It appears that the isooctanoic-benzoic condensate at the 1.5/1.5 ratio yields a lower oxazoline ring content.

Group IX.Gives the various ratios of 2-ethylhexoic to benzoic acid studied. Hydroxyl excesses were used be- Group X.-Treats the same 2-ethylhexoic with PTBBA.

A tendency of crystallization at 1.5 and 2/1 ratios of Group XI.--Represents the preparation of condensates from Z-amino-Z methyl, 1,3-propandiol.

OH/COOH.--Total ratio of amine and hydroxyl in Tris Amino to carboxyls in acids.

ingre residual hydroxyl again was essentially close to zero. It is presented because the isononanoic was the same sample used in Example 20. However, it was a 5 gal. batch versus a flask for Example 20.

cause of some difficulty in completing reaction. 2-ethylhexoic is a secondary acid.

PTBBA was noted in examples not reported in Table II. Again, hydroxyl excess was used.

problem and, therefore it is desirable to carry out these reactions over the somewhat prolonged period of from 7 to 50 hours necessary to obtain the desired acid value in the absence of a catalyst. No color difficulty was experienced with triphenyl phosphite, however. Also, this catalyst may be added at the beginning of the first stage. It has been found that the presence of solvent such as aromatic hydrocarbon tends to promote oxazoline ring formation, a desired and characterizing feature of the esters of this invention. From 1% to 10% by weight of the esterification mixture of solvent is added as early as possible in the reaction. Specific aromatic hydrocarbon solvents include benzene, toluene and xylene. The solvent may be added prior to reaction, or initially, or it may be added gradually in the course of the esterification.

The reaction is usually carried out in two stages, in the first of which the temperature is gradually increased to a maximum from about 375 F. to 420 F., preferably 375 F. to 400 F. Following the addition of the second acid, the temperature is increased, usually to a range of 390 F. to 425 F., where the reaction is maintained till an acid value of 10 or below; preferably below 5 is reached. Higher temperatures may be used in the second stage but are generally not considered preferable.

The total reaction time may vary from 7 to 50 hours. The time for a given stage of the reaction is determined by arrival at a predetermined acid value or acid value range. The final acid value of the vehicles of this invention is 10 or below, and preferably below 5. Following the addition of the second acid, the temperature may be increased, usually to within a few degrees of 425 F. Where the reaction is maintained for a period of, time approximately equal in time to stage one, that is, from 7 to 50 hours, and as indicated above, the acid value is generally less than 10. The time for a given stage of the reaction is determined by arrival at a predetermined acid value or within a range of acid values.

At the conclusion of the reaction, any solvent which has been used is desirably stripped off, if this can be done conveniently without impairing the color of the vehicle. Usually from 1% to 10% of the end product constitutes solvent due to difficulty in removing all of the solvent without sacrificing color.

In general, the vehicles of this invention produced in accordance herewith generally have the following characteristics:

Acid value 1-10 Color (Gardner-Holdt) (Clear) 4-18 Viscosity (Gardner-Holdt) D-Z Weight per gallon lbs 7.9-9.1 Percent solids 82-99 Percent oxazoline 60-100 Molecular weight 450-503 The color bases of the present invention are an improvement upon the universal color bases described and claimed in application Ser. No. 611,372 filed Jan. 24, 1967, by James A. Arvin and Mary G. Brodie, now abandoned.

Inclusion of the rather specific solvent system of the present invention renders the universal shading compositions of the aforementioned Ser. No. 611,372 more adaptable for use in a wide variety of lacquers and enamels. While the emphasis has been placed upon automotive refinishing lacquers by way of example, it is to be understood that such emphasis is by way of example only and not by way of limitation. The color bases of the present invention are useful broadly in enamels and lacquers regardless of the substrate to which they are applied.

Particularly suitable solvent systems include the following:

EXAMPLE S-l Parts Propylene glycol mono-methyl ether 21.5 Xylene 7.0

12 EXAMPLE S-2 Propylene glycol mono-methyl ether 30.8 Xylene 28.0

EXAMPLE S-3 Propylene glycol mono-methyl ether 23.0 Xylene 6.6

EXAMPLE S-4 Propylene glycol monomethyl ether 20.0 Xylene 6.0

EXAMPLE S-5 Propylene glycol mono-methyl ether 49.0 Xylene 16.0

:EXAMPLE S-6 Propylene glycol mono-methyl ether 50.0 Xylene 17.0

EXAMPLE s-7 Propylene glycol mono-methyl ether 20.0 Benzene 20.0

EXAMPLE S-8 Propylene glycol mono-methyl ether 25.0 Benzene 7.2

EXAMPLE S-9 Propylene glycol mono-methyl ether 30.0 Toluene 30.0

The color bases of the present invention are formed by adding the foregoing solvent systems, or their equivalent, to previously prepared universal color bases formed by grinding pigmentary material into one of the examples of vehicles such as those exemplified in Table II. As indicated above, the grinding is carried out by conventional attrition mill means, and a predetermined amount of the solvent system merely added to the color base.

The following examples illustrate color bases of pre ferred compositions for use in forming the specific color bases of the present invention.

EXAMPLE CB-l Parts by Weight Titanium dioxide 62.5 Vehicle of Example 9, Table II 9.0

EXAMPLE CB2 Ferrite yellow pigment 38.0 Vehicle of Example 9, Table II 3.2

EXAMPLE CB-3 Medium chrome yellow pigment 65.0 Vehicle of Example 10, Table II 5.4

EXAMPLE CB-4 Copper phthalocyanine (blue) pigment 20.0

Vehicle of Example 9, Table II 4.0

EXAMPLE CB-S Lampblack 11.0

Vehicle of Example 9, Table II 24.0

EXAMPLE CB-6 Carbon black 12.5

Vehicle of Example 9, Table II 20.5

As indicated above, these universal color bases are prepared by merely grinding the pigments into the vehicles to a predetermined Hegman grind, for example, 7+. The ratio of pigment to vehicle in the foregoing examples is in the range of 46:1200 parts by weight per parts of vehicle by weight.

The following examples are formulations for mixing color bases in accordance with the present invention 13 which are particularly useful in formulating enamels or lacquers substantially independently of the type of vehicle or binder which characterizes the enamel r lacquer. These mixing color bases are prepared by adding the solvent systems of the preceding set of examples bearing the S- numbers to the color bases of the next set of examples bearing the CB- numbers to give compositions typical examples of which have the following analyses:

EXAMPLE MCB-l Parts by weight Titanium dioxide 62.5 Vehicle of Example 9, Table II 9.0 Propylene glycol mono-methyl ether 21.5 Xylene 7.0

EXAMPLE MCB2 Ferrite yellow 38.0 Vehicle of Example 9, Table II 3.2 Propylene glycol mono-methyl ether 30.8 Xylene 28.0

EXAMPLE MCB3 Medium chrome yellow 65.0 Vehicle of Example 10, Table II 5.4 Propylene glycol mono-methyl ether 23.0 Xylene 6.6

EXAMPLE MCB4 Copper phthalocyanine (blue) pigment 20.0 Vehicle of Example 9, Table II 54.0 Propylene glycol mono-methyl ether 20.0 Xylene 6.0

EXAMPLE MCBS Lampblack 11.0 Vehicle of Example 9, Table II 24.0 Propylene glycol mono-methyl ether 49.0 Xylene 16.0

EXAMPLE MCB6 Carbon black 12.5 Vehicle of Example 9, Table II 20.5 Propylene glycol mono-methyl ether 50.0 Xylene 17.0

The ratio of total solvent to vehicle in the foregoing examples is in the range of 48:1840 parts by weight per 100 parts by weight of vehicle.

The foregoing compositions are typical examples of the present invention. Those skilled in the art will be able to formulate numerous other examples in accordance with the teachings hereof using different pigments and different vehicles from the chart comprising Table H as well as different solvent systems in accordance herewith.

The color bases of the present invention are especially useful to provide a color to a given base coating composition of the lacquer or enamel type, and especially those useful for automobile refinishing purposes. The color bases of this invention are used pursuant to a formula whereby quantities of such bases which are measured in terms of cubic centimeters per quart or per gallon of base coating composition are added to the base coating composition pursuant to said formulation. When these concentrated colors are mixed into the color base, such as by shaking the resultant formulation on an oscillatory paint mixing machine, or by simple stirring in, there results a colored coating composition which is a match for an original coating composition which appeared on the automobile, for example, and which render a repair body surface indistinguishable from the balance of the body upon drying. The formulation of these color bases into a base vehicle, which may be either pigmented or clear, according to the particular system employed by the manufacturer, is carried out. by well known and conventional methods. The only change that has been made in conventional systems is that the color bases of the present invention are of such a character that they may be used with a wide variety of base vehicles such as are encountered in the field as enamels or lacquers.

What is claimed is:

1. A mixing color base for lacquer and enamel types of coating compositions comprising in combination:

(a) a paint pigment,

(b) a Newtonian, normally liquid, non-polymeric nondrying mixed aliphatic-cyclic ester of an oxazoline, the precursor of which is a tri-(hydroxy-alkyl) amino alkane characterized by the presence therein of a heterocyclic oxazoline ring wherein:

(1) the alkyl group contains 1 carbon atom and the alkane group contains 1 to 2 carbon atoms;

(2) the aliphatic moiety is derived from a saturate of aliphatic mono-carboxylic acid having an iodine value less than 160; and

(3) the cyclic moiety is derived from a monocyclic monocarboxylic acid;

(c) propylene glycol mono-methyl ether; and

(d) a normally liquid aromatic solvent, the ratio of (a) to (b) being in the range from 46:1200 parts by weight per 100 parts by weight of (b); the ratio of (c) plus (d) to (b) being in the range of from 48:1840 parts by weight per 100 parts by weight of (b); and the weight ratio of (c) to (d) being in the range of from 30:70 to :30.

2. A color base in accordance with claim 1 wherein the aromatic solvent is an aromatic hydrocarbon.

3. A color base in accordance with claim 1 wherein the aromatic hydrocarbon is xylene.

4. A color base in accordance with claim 2 wherein the tri-(hydroxy-alkyl) amino alkane is tris-(hydroxymethyl) amino methane.

5. A color base in accordance with claim 1 wherein the aliphatic moiety is derived from iso-decanoic acid.

6. A color base in accordance with claim 1 wherein the cyclic moiety is derived from benzoic acid.

7. A color base in accordance with claim 4 wherein the aliphatic moiety is derived from iso-decanoic acid and the cyclic moiety is derived from benzoic acid.

8. A color base in accordance with claim 7 wherein the aromatic solvent is xylene.

References Cited UNITED STATES PATENTS JAMES E. POER, Primary Examiner US. Cl. X.R. 1063 1 l 

